1. Open Your Image in Photoshop
* Go to `File > Open...` and select the portrait you want to edit.
2. Select the Magnetic Lasso Tool
* Find the Lasso Tool in the Toolbar (usually on the left side of your screen). It might be nested with other Lasso tools.
* Click and hold on the Lasso Tool icon. A flyout menu will appear.
* Select the Magnetic Lasso Tool.
3. Adjust the Magnetic Lasso Tool Settings (in the Options Bar)
Before you start tracing, take a look at the options bar at the top of your Photoshop window. These settings will affect how the tool behaves. Experiment with these settings to find what works best for your image:
* Width: (Pixels) This determines how far the tool will search for edges to snap to. A higher number means it will look farther away from your cursor. Start with a value around 10-20 pixels and adjust as needed. If the tool keeps grabbing onto the wrong things, lower the Width.
* Contrast: (Percentage) This determines how much contrast the tool needs to see in order to detect an edge. A higher number requires a stronger contrast difference. If you are working with a low-contrast image, lower the Contrast. Try starting around 10-20%
* Frequency: This determines how often Photoshop places anchor points along your selection. A higher frequency means more anchor points, resulting in a more precise selection, but also a potentially slower workflow. Start around 50-60 and adjust if needed.
* Lasso Options: These are usually: `New Selection`, `Add to Selection`, `Subtract from Selection`, `Intersect with Selection`. Make sure `New Selection` is selected to start a new selection. You can switch to `Add to Selection` or `Subtract from Selection` later to refine the selection.
4. Start Tracing the Subject
* Click Once to place your first anchor point along the edge of your subject. This is the starting point of your selection.
* Move Your Mouse Along the Edge of the Subject. You don't need to click continuously. The Magnetic Lasso Tool will automatically try to find the edge and snap to it, placing anchor points as you move.
* Be Precise: Move slowly and carefully along the edge of your subject. If you make a mistake and the tool jumps to the wrong area, just press the Delete/Backspace key to remove the last anchor point and retrace that section.
5. Completing the Selection
* Close the Selection: When you reach the starting anchor point, hover your cursor over it. A small circle will appear next to the cursor. Click to close the selection. This will create a selection outline around your subject.
6. Refine the Selection (Optional but Recommended)
The Magnetic Lasso Tool is good, but it's rarely perfect. Use the following tools to refine your selection:
* Add to Selection (Shift Key): Hold down the Shift key while using the Magnetic Lasso Tool to add any areas that were missed during the initial selection. Click and drag to add the missing parts.
* Subtract from Selection (Alt/Option Key): Hold down the Alt/Option key (Windows/Mac) while using the Magnetic Lasso Tool to subtract any areas that were incorrectly selected. Click and drag to remove those parts.
* Select and Mask Workspace: For more complex refining, use `Select > Select and Mask...`. This workspace offers more advanced tools for fine-tuning the edges of your selection, particularly for dealing with hair or other soft edges. Use tools like the Refine Edge Brush to improve the selection's quality.
7. Invert the Selection
Since you want to blur the *background* and not the subject, you need to invert the selection. Go to `Select > Inverse`. Now the background is selected.
8. Apply the Gaussian Blur
* Go to `Filter > Blur > Gaussian Blur...`
* A dialog box will appear. Use the Radius slider to control the amount of blur. A higher radius value will create a stronger blur. Start with a small value (e.g., 2-5 pixels) and gradually increase it until you achieve the desired effect. The ideal radius depends on the resolution of your image and how much blur you want.
* Check the "Preview" box to see the effect of the blur in real-time.
* Click OK to apply the blur.
9. (Optional) Add a Layer Mask for Non-Destructive Editing
Instead of directly blurring the background, which is destructive, consider using a layer mask:
* Make sure the background is still selected (after the inverse).
* In the Layers Panel (usually on the right), select the layer with your image.
* Click the "Add Layer Mask" button at the bottom of the Layers Panel (it looks like a rectangle with a circle inside). This will create a mask linked to your layer. The selected area (the background) will be *revealed*, and the subject will be *hidden* in the mask.
* Now, apply the Gaussian Blur filter: `Filter > Blur > Gaussian Blur...` as described above. Since you're blurring the entire layer, the mask controls *which* part of the blur is visible. This allows you to change or remove the blur later without affecting the original image.
10. Saving Your Image
* Go to `File > Save As...`
* Choose a file format that supports layers (like .PSD) if you want to preserve the layer mask and be able to edit the image later.
* If you just want a flattened image to share, choose .JPG (for photos) or .PNG (for graphics).
Tips and Considerations:
* Zoom In: Zoom in close to the edges of your subject to make more accurate selections.
* Start with Good Lighting: Images with clear separation between the subject and background are easier to work with.
* Feather the Selection (Sometimes): Before blurring, you *might* want to feather the selection slightly (`Select > Modify > Feather...`). A small feather (e.g., 1-2 pixels) can soften the edges of the selection and create a smoother transition between the blurred and unblurred areas. However, this isn't always necessary, and can sometimes create unwanted halos.
* Be Careful with Hair: Hair can be tricky to select. The `Select and Mask` workspace is extremely useful for refining selections around hair.
* Practice: The more you use the Magnetic Lasso Tool, the better you'll become at making precise selections.
* Consider Content-Aware Fill (for simpler backgrounds): If the background is fairly uniform, you could select the subject, invert the selection, and then use `Edit > Fill > Content-Aware` to remove the background entirely and let Photoshop fill it in. This works best with simple backgrounds like a solid color or blurry patterns.
* Use Different Tools: The Magnetic Lasso Tool isn't always the best choice. Depending on the image, the Quick Selection Tool, Magic Wand Tool, or even the Pen Tool might be more appropriate. Don't be afraid to experiment!
* Experiment with other Blur types: Try `Field Blur` or `Iris Blur` from the Blur Gallery for different effects. These allow you to control the blur more precisely across the background. The Iris Blur is especially useful for creating a shallow depth-of-field effect.
By following these steps, you can effectively blur the background of your portraits in Photoshop using the Magnetic Lasso Tool and create a more professional and eye-catching result. Remember to practice and experiment with different settings to achieve the best outcome for each image.